1. Field of the Invention
The invention concerns a power laser pulse generator and, notably, a generator giving one pulse from several pulses.
2. Description of the Prior Art
Presently known power lasers generate pulse trains with a peak power that is as yet insufficient.
For example, the pulses emitted by a FEL (free-electron laser), as shown in FIG. 1, typically have the following characteristics:
Micropulses with t=40 .mu.s; PA1 Peak power of the micropulse: I.sub.c =200 MW PA1 Distance between micropulses: T=100 ns; PA1 Number of micropulses: N=2.10.sup.3 PA1 Wavelength: near IR. PA1 a laser source emitting at least one pulse train with a period t; PA1 a ring-shaped optical cavity with a length proportional to the period t of the pulse train; PA1 a non-linear medium inserted in the ring of the optical cavity receiving the pulse train that acts as a pump beam for the non-linear medium, with the light circulating in the cavity acting as a signal beam; PA1 means that are integrated into the optical cavity and act at determined instants to extract a light pulse from the optical cavity.
In certain applications, it is desired to obtain a peak power higher than that obtained by means of a FEL laser, for example by generating a single pulse, but one having a peak intensity that is N times the intensity of a pulse (see FIG. 2). N is the number of micropulses contained in the pulse emitted by the FEL (N=10.sup.3).
The invention concerns a device that enables the adding up of N micropulses of a train of pulses to give a single pulse of greater amplitude.
The means implemented to obtain this addition of pulses in a single pulse are compatible with the power densities brought into play in lasers of this type. In particular, the device of the invention excludes the use of components that absorb a component of polarization and enable adaptation to wide-diameter beams in order to reduce the power densities on optical windows and mirrors.